This invention relates to a silicon nozzle formation method in which a multi-nozzle for an ink jet printer is formed, utilizing the anisotropic etching properties of single crystal silicons. The invention is particularly adopted to increasing the strength and overall utility of nozzles thus formed.
An ink jet multi-nozzle manufacturing method has been proposed in the art, in which, as shown in FIG. 1(a), a silicon single crystal is subjected to etching after a mask is placed on the &lt;100&gt; surface thereof exposing only the area (A). Due to the anisotropic etching properties of such silicon crystals, the resulting multi-nozzle is readily formed and is generally of high quality. Referring to FIG. 1(a), the etching angle .theta. is set to 54.7.degree. in order to maximize the anisotropy of the silicon crystal. In order to form nozzles 3 at a small pitch, it is therefore necessary that the maximum thickness T of a single crystal silicon plate be equal to the nozzle pitch. For instance, in order to obtain a nozzle pitch of four nozzles per millimeter (mm), the thickness of the single crystal silicon plate should be of the order of 0.1 to 0.2 mm, taking into account the width (B) of each nozzle at its opening.
When the single crystal silicon plate is subjected to anisotropic etching, the single crystal silicon plate 12 is mounted on a holder 19 as shown in FIG. 1(b), and is fixed with retainers 20. An etching solution 17 is then applied to the single crystal plate 12. Under the above-described circumstances, due to the fact that the crystal plate 12 is of small width, it is impossible to sufficiently tighten the crystal plate 12 with the retainers 20. This in turn creates the probability of the etching solution leaking into the crystal plate at points other than those intended, i.e., other than the exposed portions that have not been masked.